Arsene Wenger was left with egg on his face after making nine changes for the FA Cup tie with Nottingham Forest punishing a poor Arsenal side.
The holders are out, meaning Wednesday's tie with Chelsea is even more crucial and probably the Gunners' biggest chance of silverware, given the arrival of Champions League sides in the Europa League.
The champions remain in the cup after being held by Norwich, but also made nine changes, meaning both teams will bring back their best line-ups midweek.
Wenger will likely leave several of today's team out in the cold for the next few weeks and some could even see the exit.
Here are football.london's player ratings:
David Ospina
Made some excellent saves in the first half as Forest pressed forward, but possibly could have done better with the first goal as it was swung in to the near post. 6
Rob Holding
Looked sluggish and nervous throughout alongside Mertesacker. Struggled to deal with the pace and intensity of Forest's attacking play. Gave away the penalty to cap an utterly miserable display. 3
Per Mertesacker
The big German scored Arsenal's goal but was given a torrid afternoon by Ben Brereton, he just could cope with the Forest frontman who ran at him every time he could. 3
Mathieu Debuchy
Got forward well on a few occasions, but like his fellow defenders he was pulled put of position far too easily as Forest attacked with pace. 4
Reiss Nelson
A real bright spot in an otherwise miserable 90 minutes. Attacked with intent and looked as likely as anyone to make something happen. 6
Ainsley Maitland-Niles
Combined well with Nelson at times and produced one magical moment of skill in the first half. One of Arsenal's better players. 5
Joe Willock
Never really got into the game at all. Overrun in midfield before being replaced by Nketiah. 4
Mohamed Elneny
No influence at all, despite being one of the most experienced players on the pitch. Offered no protection to the defence and nothing going forward. 4
Alex Iwobi
Another poor performance from a player horribly out of form. Played in a deeper role than normal but couldn't influence the game. 4
Danny Welbeck
Never really looked like scoring, but to his credit he stayed switched on to take advantage of Jordan Smith's mistake. Aside from that a really poor display. 5
Theo Walcott
No impact whatsoever, apart from the free-kick which led to the first goal. Did his chances no good of forcing his way into the Premier League side. 4
Substitutes
Eddie Nketiah
Created one good chance for himself but was denied by Jordan Smith's legs. 5
Chuba Akpom
Thrown on for the last few minutes and missed a good chance to make it 4-3. 5